Collaboration, Making Animated Performances Feel Real, and Humanizing a Tree for Guardians of the Galaxy

With SIGGRAPH located in Vancouver, I took advantage of the opportunity to catch up face to face with Nicolas Aithadi, visual effects supervisor at MPC for Guardians of the Galaxy. Aithadi, who has 20 films to his credit, received Oscar and BAFTA nominations in 2011 for Harry Potter and the Deathly Hallows: Part 1, a 2010 BAFTA nomination for Harry Potter and the Half-Blood Prince, and a 2006 VES nomination for compositing Harry Potter and the Goblet of Fire. In July, he moved to MPC’s Vancouver offices to work on Monster Trucks, a live-action/animation hybrid directed by Chris Wedge scheduled for May 2015. Prior to that, at MPC in London, he supervised a crew of 700 there, in Vancouver and in Montreal, who worked on Guardians, a project that stretched over 16 months.

Now in its fifth week of release, Guardians of the Galaxy has continuously held first place at the box office, has become the highest-grossing movie of the year domestically. Worldwide, the film has tallied more than $550 million in box office receipts. James Gunn directed the critically acclaimed film. Overall visual effects supervisor Stephane Ceretti led work by MPC, Framestore, Method Studios, Cantina Creative, Proof, Luma Picture, and The Third Floor. 

The irreverent scifi action/adventure produced by Marvel Studios and distributed by Walt Disney Studios features two CG characters: a humanoid tree named Groot, voiced by Vin Diesel and a rascally raccoon named Rocket, voiced by Bradley Cooper. Aithadi led MPC’s work on Groot, several digital environments, and a climatic battle sequence; 857 shots in all, with Groot in nearly half. 

As we waited for my meeting with Aithadi, MPC publicist Jonny Vale gave me some unexpected background information. “Nicolas is a chef,” he said. Then, when Aithadi arrived, Vale introduced us and left.

Aithadi is 42, medium build, with a clipped beard and short dark hair. He wore a black baseball cap with a lion’s head on a white patch in front. Later, I would learn he has 15 different animal caps, that except for black tie events he always wears a baseball cap, and that he began the practice in the 90’s when his head was shaved during compulsory military service in France. 

“You’re a chef?” I ask as we walk to a nearby café.

“I cook,” he says. Born and raised in Paris, Aithadi speaks with a French accent. 

“What do you cook?”

“French food,” he laughs. “I like precise cooking. I don’t cook to eat. I eat it, but it’s more about creating a nice presentation.”

He shows pictures on his cell phone of food beautifully plated: A salad with blue potatoes, a main dish with carrots, red peppers, monkfish, and edible flowers, the colors and textures in each artfully arranged. “It’s like art,” I say.

“It goes with my job,” he says. “I’m kind of a … for me, every detail is important. I want to make everything perfect.” 

We scoot into a Korean restaurant and order. “Something simple,” Aithadi requests. When the food comes, we settle in to talk about Groot and Guardians.

All images © 2014 Marvel Studios

“I love Groot,” Aithadi says. He’s one of many fans now. Baby Groot, who dances at the end of the film to The Jackson Five’s “I Want You Back,” has already become a collectible bobblehead toy. MPC animation supervisor Greg Fisher and his team performed Baby Groot and the far more serious adult who appears throughout the film.

“I love Rocket as well,” Aithadi says. “He’s a great character. But there’s something about Groot’s eyes. He’s alive.”

During pre-production, artists at MPC developed Groot, and those at Framestore handled Rocket. During post-production, the studios shared shots, although generally MPC did shots with close-up acting of Groot and Framestore performed Rocket’s close-ups. 

“The level of sharing assets was crazy,” Aithadi says, noting that, fortunately, the two studios are just one street apart. “We were going to Framestore and they were coming here. The whole team — animation, rigging, CG supes. The goal was to create one Rocket and one Groot, so it was very important that we knew we were working on the same thing. It was all driven by James Gunn. He had in his head who Rocket and Groot were.”

Early in post-production, Fisher provided Groot’s voice. Later, the animators changed the lip sync to match Vin Diesel’s voice. 

“We didn’t have to change much,” Aithadi says. “The intent was there. He only ever said ‘I am Groot,’ so we had to make sure you understood if he was happy, or sad, or nonchalant. When we looked at Greg doing Groot, we realized the eyes were very important.”

The Eyes Have It

The artists began, as is usually the case, with reference. “We looked at every type of eye we could find to understand why an eye looks real,” Aithadi says. “When you do eyes in CG, they look kind of dead. It always goes back to the same thing in CG: It’s the details. As good as we had done eyes before, they weren’t detailed enough.” By adding details such as textural displacements on the iris, the artists began to give Groot’s eyes more life.

“When you look at a close-up of an iris, it looks like a mountain ridge,” Aithadi says. “By displacing the iris, we created shadows inside the iris. It sounds like overkill, but it added a layer of detail we didn’t have before. We also added a tissue layer between the iris and the sclera that contributed to the softness of the iris and the eyeball, and we made sure we had meniscus in that layer of wetness that connects the eye to the eyelid.”

When finished, the artists rendered the eye with caustics so light would reflect and refract on the eye. But all that attention to detail still wasn’t enough.

“The eyes looked really cool,” Aithadi says. “We have a close-up of Groot and you can look inside his beautiful, beautiful eyes. But something was missing. So we did one more stupid little thing. We made the eyes a bit cross-eyed. They weren’t in the same position. That bit of weirdness made the face look strange, and that made it look real. People are not perfect, and CG perfection is the worst enemy of visual effects.”

To sculpt Groot’s body, modelers worked in ZBrush from concept art provided by Marvel. 

“That’s what we used for the test, and it was cool, but it wasn’t Groot,” Aithadi says. “He looked too much like a tree. From the version at ComiCon to the final version, we did hundreds of iterations. We changed his arms, his face, every single thing. And every time we did, we gave a new version to Framestore. I think they hated us.”

Into the Woods

To humanize the tree, the MPC artists gave Groot a bipedal body, and then considered how to turn the wooden character into a living, breathing creature.

 “We looked at what makes fleshy characters look alive and realized it’s the muscles and skin that you see moving,” Aithadi says. “We didn’t have that with Groot. That’s when we decided to build him out of individual branches with each rigged individually.”

Animators worked with a typical bipedal skeleton to create Groot’s performance, and his performance triggered an automated system that jiggled and moved the branches. 

“All the dynamics were on sliders,” Aithadi says. “We could dial the movement up and down. When Groot moved his arm, you could see branches moving like tendons and pectorals in a muscle system. We had a utility so that no branch would interpenetrate another while moving. We had plates on his body that moved dynamically like pectorals. It was the most complex rigging system we’ve ever done at MPC. When we gave it to Framestore, we were scared they’d poach Ben Jones, our lead rigger, and try to hire him.”

The rig for Groot’s body was complicated, but it wasn’t the most complicated. That was Groot’s face.

Face Time

“We had this idea that it would be cool if Groot’s face wasn’t elastic and bending all the time,” Aithadi says. “So we thought we could separate the face into plates and animate them. That was a good idea on paper, but when the plates weren’t moving, when they were in a neutral position, they had to be invisible. You couldn’t have a clue that they would separate. When Groot gets angry, he opens his face up so much he looks scary; the plates look like spikes. But the plates never detach. There is never a hole. We modeled them like this:” 

Aithadi takes the paper his chopsticks came in and folds each side toward the center to demonstrate. He pushes the ends of the paper toward the center to bring the folds together and then pulls them apart.

“You should have seen Framestore when we sent the face to them,” Aithadi says. “It’s proprietary technology, so we couldn’t give them the rig. We gave them the model that was split and the animation, and Ben [Jones] wrote technical documentation for the riggers. But they had to make it up.”

Branching Out

In addition to being able to move like a human and dance like a baby, the character grows branches, his arms extend, and he can grow shields and leaves. Ben Jones developed the branch-growing setup. 

“The first setup didn’t work,” Aithadi says. “It looked like a wipe. So, one day Ben found a fantastic solution. We were looking at time-lapse photography to see how things grow, and he realized that the longer a branch gets, the heavier it gets. So he added gravity. It had looked like a wipe before because the branch was growing in a vacuum. Also, when we looked at time-lapse video, we always saw some sort of trembling when the branch shoots out and then goes down. So he added wobble. Those two things, gravity and wobble, wiped the wipe.”

Although Groot initially took six months to develop, refinements continued through the end of the 16 months of post-production.

“James [Gunn] said from the beginning, 'If Rocket doesn’t work, the film doesn’t work,'” Aithadi says. “Then it was  'If Groot doesn’t work, the film doesn’t work.' Then, it was funny, every single thing in every single shot became the most important thing. What’s cool, though, is that when I read reviews of the film, the critics don’t talk about the CG characters, they talk about them like actors — like amazing characters in the film, not amazing CG characters.”

Aithadi credits Gunn’s unique approach with the characters becoming such an accepted part of the film. “With CG characters, most of the time when you don’t need them, you don’t do them because of budget,” he says. “But James [Gunn] asked us to do Groot and Rocket even if you’ll see only a piece of them, because if they were real actors, they’d be there. You might see the top of an ear, a little bit of foot. We had shots where you just see an arm or a shoulder or an ear. You believe Groot is in the film because he is there even when he wasn’t shot. I think that was really cool, really clever.”

Some people move into visual effects though an amazing variety of channels — animation, architecture, engineering, photography and even, we’ve learned, furniture making. Aithadi began his career as an artist, by drawing. 

“It was what I knew how to do naturally,” he says. “I stopped school when I was 18 because most of my time, I was drawing, so I decided to do my own thing. I started work as an illustrator for newspapers. The paradox is that it wasn’t hard to get a job without a diploma. Since it’s all about images, you show something and if they like it you get the job.”

Soon, he was drawing stills for video games, a short career interrupted by his compulsory military service. 

“When I came back, I started working with computers,” he says. “I begged my mom to buy one. It was extremely expensive, but she paid in installments, so I had a Pentium 90 with 128 MB and I started to learn.”

When he became comfortable working with 3D software, he found for a job in broadcast. That job led to two years at ExMachina and three at Duboi in Paris, and then MPC in London and eventually, while there, an Oscar nomination.

“Drawing was fine, and it was easy for me, but I wasn’t fascinated by it,” he says. “Something was missing. When I discovered computers, I knew the missing thing was images in movement. I found it in computer graphics. I’m not into animated films. I like to have CG attached to something. I love visual effects that help live action.”

Like Groot and the other CG effects in Guardians. He’s eager to credit the rest of the team’s work on the film.

Guardians was a hard film to work on,” he says. “The scope on this film was ridiculous. We did Morag, the planet at the beginning of the film. A gigantic geyser 700 meters tall, like two Eiffel Towers. One billion particles. The biggest simulation we’ve done. We did the Xander sequence. The city had 39 billion polygons. We had a team that only took care of spaceships. We did the final battle, 490 shots. People think that because Framestore did Rocket, we shared the battle, but we did the whole sequence. The battle had 7000 explosions, 40,000 ships. One shot alone had 400 explosions in it. At the end, we had nearly 100 compositors shoving out 70 shots a day. Usually with a movie, you start with the easy shots. In this movie, there weren’t any. We had a CG character with a CG city behind. But the great thing with Guardians is the reception. I enjoyed being in the cinema listening to people. It makes it all worth it.”

We finish eating. While we wait for the check, Aithadi tells me the story about the baseball cap. And then it’s time to get back to work. He has a call scheduled with a producer. 

“I love this job because I learn about things,” he says as we leave. “I learned a lot about architecture and landscaping to build the city for Guardians. And I’ve never learned how to drive, but I have to learn about cars for this next film. It wouldn’t be fun if I were just executing. The cool stuff is bringing a little of what you like into a film. If I can manage to bring what I like all the way through the process and convince everyone it’s a good idea, that’s fantastic. I love film. But this job is so hard, especially today compared to 10 years ago, if I didn’t have that outlet, if it was just ‘Where do you want it?’, I would be growing tomatoes and cooking.”